管理措施对三江源区"黑土滩"土壤肥力及土壤酶活性的影响

对三江源区典型退化草地“黑土滩”采取施肥及种植垂穗披碱草的恢复措施,结果表明,土壤中的全氮与有机质的相关性显著,全磷与有机质的相关性较明显,变化趋势相一致。短期的恢复措施造成了恢复样地20~30 cm土壤层中有机质、全氮和全磷含量的下降,长期的恢复措施使恢复样地中的这3种营养物质的含量得到了上升;人工种植措施使土壤中的全钾含量显著下降(P<0.05)。此外,速效养分的变化不一致,其中速效氮的含量表现为先降低后升高,速效磷和速效钾的含量变化表现出升高趋势。植被恢复对土壤脲酶活性有促进作用,但蔗糖酶活性没表现出规律性变化;这2种酶的活性与速效养分的含量表现出较强的正相关,而与有机质和全价养分的含量相关性不显著。

Effect of managerial measures on changes of soil enzyme and soil fertility in "black soil bleach" degraded grassland

The effect of managerial measures on changes of soil enzyme and soil fertility in "black soil bleach" degraded grassland showed that total N and P were closely related to soil organic matter.The variances in different soils and soil layers were nearly the same:the short term vegetation restoration caused a reduction in the soil organic matter and total N and P of the 20-30 cm layer while long term vegetation restoration caused the contents of the three nutrients to slowly increase although total K significantly(P<0.05) decreased.The available N decreased at first then increased with time and the contents of available P and K also increased.Vegetation restoration promoted the activity of urease but the activity of sucrase was irregular.The activities of soil urease and sucrase had little correlation with soil organic matter and total N,P,and K,but had a strong positive correlation with available nutrient.This may be the reason alpine meadows lack available nutrients.